使用C++调用windows API，编写GUI界面，用来输出多幅图像

以下是一个简单的使用C调用Windows API编写GUI界面的示例，用于输出多幅图像：

#include <windows.h>

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    HWND hwnd;
    MSG msg;
    WNDCLASS wcls;

    // 定义窗口类
    wcls.style = CS_HREDRAW | CS_VREDRAW;
    wcls.lpfnWndProc = WndProc;
    wcls.cbClsExtra = 0;
    wcls.cbWndExtra = 0;
    wcls.hInstance = hInstance;
    wcls.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wcls.hCursor = LoadCursor(NULL, IDC_ARROW);
    wcls.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    wcls.lpszMenuName = NULL;
    wcls.lpszClassName = "MyWindowClass";

    // 注册窗口类
    if (!RegisterClass(&wcls))
    {
        MessageBox(NULL, "Window Registration Failed!", "Error", MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    // 创建窗口
    hwnd = CreateWindow("MyWindowClass", "My Window", WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 640, 480, NULL, NULL, hInstance, NULL);

    if (hwnd == NULL)
    {
        MessageBox(NULL, "Window Creation Failed!", "Error", MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);

    // 消息循环
    while (GetMessage(&msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT ps;
    static HBITMAP hBitmap;

    switch (msg)
    {
    case WM_CREATE:
        // 加载位图
        hBitmap = (HBITMAP)LoadImage(NULL, "image.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
        break;

    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);

        // 将位图输出到窗口
        if (hBitmap)
        {
            HDC hdcMem = CreateCompatibleDC(hdc);
            SelectObject(hdcMem, hBitmap);
            BITMAP bm;
            GetObject(hBitmap, sizeof(bm), &bm);
            StretchBlt(hdc, 0, 0, bm.bmWidth, bm.bmHeight, hdcMem, 0, 0, bm.bmWidth, bm.bmHeight, SRCCOPY);
            DeleteDC(hdcMem);
        }

        EndPaint(hwnd, &ps);
        break;

    case WM_DESTROY:
        // 释放位图资源
        if (hBitmap)
        {
            DeleteObject(hBitmap);
        }

        PostQuitMessage(0);
        break;

    default:
        return DefWindowProc(hwnd, msg, wParam, lParam);
    }

    return 0;
}

在上面的示例中，我们定义了一个窗口类`WNDCLASS`，并在`WinMain`函数中使用`RegisterClass`函数注册该类。然后，我们创建了一个窗口，并在消息循环中使用`GetMessage`函数处理消息。

在窗口过程函数`WndProc`中，我们在`WM_CREATE`消息中加载了一个位图，并在`WM_PAINT`消息中将该位图输出到窗口中。最后，在`WM_DESTROY`消息中释放位图资源并通过`PostQuitMessage`函数终止消息循环。

要输出多幅图像，只需要在`WM_PAINT`消息中根据需要加载和输出多个位图即可。